The article examines the transformations of the philosophical concept of world as it appears in the cosmopolitan tradition of political thought and its relation to the problem of the border. It focuses particularly on how world is understood as either lost or multiplied in the contexts of modernity, globalisation, and migration. The article discusses postcolonial conceptions of cosmopolitics and the political philosophy of Hannah Arendt to show how the universal ideal of the world is replaced by singular constructions of worlds (...) in terms of the experience of migrants and refugees or the phenomenological horizon of political action. I conclude by suggesting that Jacques Rancière’s understanding of politics as a conflict of worlds can take us beyond the traps of both cosmopolitan universalism and the phenomenological singularity of being-in-the-world. (shrink)